Electrical resistivity imaging for the characterization of the Montaguto landslide (southern Italy)

Electrical Resistivity Tomography surveys were carried out for the characterization of the Montaguto earth-flow, located in the southern Apennines chain (Campania Region, southern Italy). The earth-flow investigated is one of the largest and most complex landslides in Europe with a length of 3.1 x 10(3) m, a width ranging between 45 and 420 m and an area of about 6.6 x 10(5) m(2). In the spring of 2010, a large reactivation of the earth-flow heavily damaged some strategic infrastructures. In order to mitigate the effects of the mass movement, considerable efforts were carried out by the Italian National Civil Protection Department (DPC) to tackle the emergency. The aim of the study was to contribute to a more accurate geometric reconstruction of the landslide body and to improve the knowledge of the geological setting. Due to the lithological characteristic of the outcropping lithotypes, i.e. Faeto Flysch (calcarenite, clay and marl) and Villamaina Unit (sand and silty clay), the electrical resistivity contrasts were not very pronounced. However, the high-resolution of the electrical tomographies was the key to observe the presence of both lateral and vertical discontinuities that were associated with lithological boundaries, structural features and sliding surfaces. The results of the geoelectrical surveys could be considered for planning additional and more appropriate actions aimed at the stabilization of different portions of the Montaguto landslide.